Highly Emissive Organic Single‐Molecule White Emitters by Engineering o‐Carborane‐Based Luminophores

Abstract

The development of organic single-molecule solidstate white emitters holds agreat promise for advanced lighting and displaya pplications.H ighly emissive single-molecule white emitters were achieved by the design and synthesis of as eries of o-carborane-based luminophores.T hese luminophores are able to induce multiple emissions to directly emit high-purity white light in solid state.Bytuning both molecular and aggregate structures,asignificantly improved white-light efficiency has been realized (absolute quantum yield 67 %), which is the highest value among the knowno rganic singlemolecule white emitters in the solid state.The fine-tuning of the packing modes from H-to J-and cross-stacking aggregates as well as intermolecular hydrogen bonds are successful in one molecular skeleton. These are crucial for highly emissive whitelight emission in the solid state.

Modulating Room Temperature Phosphorescence by Oxidation of Thianthrene to Achieve Pure Organic Single-Molecule White-Light Emission

“…Generally, two or three radiative excited states are designed to be responsible for simultaneous dual emission (blue and yellow/orange) or ternary emission (blue, green, and red), corresponding to two-color or three-color white-light strategy in SMWLEs, respectively. In the simplest two-color strategy, one excited state is usually the lowest singlet state (S 1 ) for blue fluorescence emission, and the other excited state can be from the charge-transfer state, 4,5 proton-transfer state, [6][7][8] excimer state, 9,10 self-assembly state, [11][12][13][14][15][16] and the lowest triplet state (T 1 ) for room temperature phosphorescence (RTP) [17][18][19][20][21][22] and other methods [23][24][25] for low-energy yellow/orange emission. According to the Chroma Theory, a standard two-color white light requires not only wavelength matching but also intensity matching between two emission spectra, indicating a rather intricate modulation between energy level and photoluminescence (PL) efficiency of two excited states.…”

Thermal Energy-Driven Solid-State Molecular Rotation Monitored by Real-Time Emissive Color Switching

“…As depicted in Figure S4b, o-1 in various solvents exhibited a dual emission affected by the surrounding solvent polarities. [43][44][45] 4.63 ns) are assigned to a single-exponential decay, originating from the TICT states. As depicted in Figure S6, X-ray diffraction (XRD) pattern of o-1, in the pristine states, exhibited an intense and sharp peak, whereas the ground powders showed no clear signals, indicative of a crystalline-to-amorphous state transition.…”

Influence of Electronic Environment on the Radiative Efficiency of 9-Phenyl-9H-carbazole-Based ortho-Carboranyl Luminophores

“…Owing to these features, such o -carboranyl compounds have recently been proposed as promising optoelectronic materials for organic light emitting diodes [ 7 , 8 ] and organic thin-film transistors [ 9 , 10 ]. The intriguing photophysical properties of o -carboranyl luminophores originate from the electronic donor‒acceptor (D–A) dyad formed by combining a π-conjugated aromatic organic fluorophore (donor) with an o -carborane (acceptor) [ 4 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. The strong electron-withdrawing ability of the carbon atoms in the o -carborane cage, which is derived from the high polarizability of the σ-aromaticity [ 37 , 38 , 39 , 40 , 41 ], allows this moiety to act as an electron acceptor during external excitation and relaxation processes.…”

“…The strong electron-withdrawing ability of the carbon atoms in the o -carborane cage, which is derived from the high polarizability of the σ-aromaticity [ 37 , 38 , 39 , 40 , 41 ], allows this moiety to act as an electron acceptor during external excitation and relaxation processes. As a result, intramolecular charge transfer (ICT) can be induced between aromatic groups and the o -carborane cage [ 2 , 4 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. The luminescence behavior of o -carborane-based D‒A dyads is characterized by the radiative decay of the ICT transition [ 2 , 4 , 7 , 8 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ,…”